Wiring/ECM voltage question

[fly89gta]

Ok, here's the deal, i'm seeing almost a full volt less to the Scanmster compared to what the battery is seeing. Granted i know through the lenght of the wiring some power will be lost, but, um not a full volt!

I check the wires that go from the battery to the ECM as far back as the firewall. Same as the what the battery has. I haven't actually checked the ECM yet.

Now on to a few questions.

Could the ECM be bad?

Also, does the ECM/chip use the voltage its seeing regarding engine operation? Meaning, will anything change if the ECM is seeing 12.7 volts instead of 13.7?

I think this is the wiring problem, but someting in the back of my head says the ECM might be bad...i don't know, my stock volt gauge is reading similar to what the scanmaster says...any opinions would be greatly appreciated

 

[fly89gta]

bttt

 

[azgn]

nothing unusual about what you are seeing....your ecm is fine, as is your battery/alternator......

 

[U1ARUNIT]

I agree, perfectly normal. My car is the same way.

 

[fly89gta]

but why such a drop? Like i said, i traced the ECM power wire to the firewall and it was still getting like 12.4 volts, so from the firewall to the ECM its losing that much? i'll take your word for it guys, i'm not going to argue with people that know more than me

i don't know, just doesn't sound right to me..but if you guys say that's fine, well then its fine

 

[U1ARUNIT]

going deeper...

There has been talk of a connection that drops gives the 1.0v that we experience, but I don't think anyone has gone far enough into it to see how, where, why, etc... At least I haven't seen the results posted here. Maybe the engineers planned it that way. Who knows!

 

[TurboDave]

As was stated, what you're seeing is pretty normal. Why you say? Good question. But there are two sources of power (12vdc) to the ECM. The one we all know about and see by the battery, plus one other that no one remembers. It's called "pwr input" at the ECM and is on pin A6. This comes from the fuze panel (labeled ECM I believe).
There's going to be some voltage drop across all that wiring and the fuze, etc. Not to worry though. The voltages going into the ECM are regulated and stepped down inside the ECM to the 5v needed to run the typical electronics inside.

 

[fly89gta]

thanks guys!!!!! you rock!!

that got rid of my worries